Location: Washington, D.C.
Three-Year Growth: 2,349.8%
2004 Revenue: $20.5 million
Employees: 12
Founded: 2000
What it does: Places ads that drive customers to bigger advertisers by giving away iPods, flat-screen TVs, and such. Why it's growing: Gratis, which has given away nearly 20,000 iPods and will soon start doling out Xbox 360 game consoles, earns $40 to $60 a pop when visitors to its website, FreePay, sign up for the not-always-free offers from advertisers including Citibank, AOL, and Blockbuster.

Inc.com is counting down to the unveiling of Inc. magazine's Inc. 500 list with a profile a day of one of this year's honorees. See other honorees in the Inc. 500 Countdown archive, and discover new winners each business day until Oct. 19, when we reveal this year's number one company.